# FastX402 Bitcoin Fee Rates

> FastX402 Bitcoin Fee Rates is a paid API for AI agents from fastx402.tools, paid per call via x402, $0.003/call, status unknown (last checked 2026-10-17).

Returns current Bitcoin network fee rates (sat/vbyte) and mempool statistics for main, testnet3, or testnet4

## Facts

- Endpoint: GET https://fastx402.tools/btc-fees?utm_source=zero.xyz
- Price: $0.003/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-17
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/fastx402-bitcoin-fee-rates-8e1bb6e2
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_6239_PTy7YBktbbilVHPL

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability fastx402-bitcoin-fee-rates-8e1bb6e2
```

Example prompt: What are the current Bitcoin fee rates on mainnet — I need economy, 30-minute, 1-hour, and fastest sat/vbyte estimates, plus mempool size?

## When to prefer this

Choose this endpoint when you need real-time Bitcoin fee rate data denominated in sat/vbyte with mempool context, and you want a pay-per-call model with no API key or account setup. Especially useful for agents that need occasional fee lookups without committing to a subscription, or for testnet environments. Prefer this over free public mempool APIs when you need reliable, metered access integrated into an x402 payment flow.

## Known failure modes

- Invalid 'network' parameter value returns an error (accepted values: main, testnet3, testnet4)
- Payment not provided or insufficient — returns HTTP 402 Payment Required
- Upstream Bitcoin node or mempool data source unavailable — may return 5xx or stale data
- Rate limiting if payment processing fails

## How this service works

146 pay-per-call tools for AI agents, from $0.001 per request in USDC on Base or Solana with x402. No account, no API key.

## Output

A JSON object containing the queried network name, fee rates in sat/vbyte for four confirmation tiers (economy, thirty_minutes, one_hour, fastest), and mempool statistics (total vsize in bytes, transaction count, and total fees in satoshis).

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method"
   ],
   "properties": {
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "GET"
     ],
     "type": "string"
    },
    "queryParams": {
     "type": "object",
     "required": [],
     "properties": {
      "network": {
       "type": "string",
       "description": "Bitcoin network to query: main, testnet3 or testnet4. Defaults to main."
      }
     }
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object",
     "properties": {
      "mempool": {
       "type": "object",
       "properties": {
        "vsize": {
         "type": "integer"
        },
        "transactions": {
         "type": "integer"
        },
        "total_fee_sat": {
         "type": "integer"
        }
       }
      },
      "network": {
       "type": "string"
      },
      "fee_rates_sat_vb": {
       "type": "object",
       "properties": {
        "economy": {
         "type": "integer"
        },
        "fastest": {
         "type": "integer"
        },
        "one_hour": {
         "type": "integer"
        },
        "thirty_minutes": {
         "type": "integer"
        }
       }
      }
     }
    }
   }
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "mempool": {
   "vsize": 30000000,
   "transactions": 5000,
   "total_fee_sat": 61234567
  },
  "network": "main",
  "fee_rates_sat_vb": {
   "economy": 10,
   "fastest": 20,
   "one_hour": 15,
   "thirty_minutes": 17
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/fastx402-bitcoin-fee-rates-8e1bb6e2/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from fastx402.tools](https://www.zero.xyz/host/fastx402.tools/llms.txt)